Cathodic protection systems commonly make use of packaged linear anodes having a variety of shapes (e.g., round, flat, or other shapes) and may be either a polymeric cable anode or a Mixed Metal Oxide (MMO) wire anode housed inside a braided or unbraided fabric housing filled with conductive backfill. These commercially available fabric-based linear anodes are similar in design and function. One particularly useful packaged linear anode for cathodic protection systems is commercially available from Matcor, Inc., the assignee of the subject invention, under the trademark SPL-FBR.
Increasingly, linear anodes are being used in conjunction with horizontal directional drilling (HDD) technology for installation. While such prior art anodes are suitable for various applications, they are not particularly suited for HDD applications inasmuch as they are prone to damage if the pulling force applied to them exceeds the pull strength of the packaged linear anode assembly. Thus, various techniques have been developed or used to attempt to minimize the potential for damaging/breaking conventional socked linear anodes during installation. One such technique entails making use of a separate, larger diameter cable with greater pull strength in conjunction with the packaged linear anode and pulling them together through the hole. Another technique entails using an oversized drill hole and additional drilling fluids to try and lubricate the hole (“muddying up the hole”) to reduce the pulling stress on the packaged linear anode. Still another technique entails using an in-line breakaway swivel to protect against over pulling the anode during installation. Yet another technique entails installation of a temporary plastic conduit pipe to case the hole and then pulling the anode through the conduit pipe casing. Once installed, the casing is pulled back out and can be reused for another pull while the anode remains in place.
All of these are workaround solutions that attempt to overcome the inherent design weaknesses of all current packaged linear anode products available on the market. Thus, a need exists for an anode assembly which overcomes the disadvantages of the prior art.
The subject invention addresses that need. In particular, the subject anode assembly is designed specifically for HDD installation and incorporates a special pulling head or nose cone and integral pulling cable system, e.g., two pulling cables, to significantly increase the pulling strength of the assembly to minimize the possibility of it breaking during installation using HDD equipment.